>> ah, i just look in the mirror, diane. i just go, okay, i got to get healthier. >> reporter: christie, who was slender and athletic as a younger man, insists his health is good. although yesterday, he told reporters -- >> if you talk to anybody in this room that has a struggle with their weight -- >> reporter: he's air waware hi weight could ultimately become a serious issue. when you look at him, do you think he's a ticking time bomb? >> i think it's really very judgmental to have such a strong conviction when you have no innate knowledge of his level of activity or his level of fitness. >> reporter: but tonight, dr. mariano fired back in a stateme statement, saying, it is sad that the governor cannot take my advice and instead chose to attack me personally. probably not going to fly with christie, who's now clear that he has no patience with people who speculate about his health before having all the facts. >> until that time, she should shut up. >> reporter: dan harris, abc news, new york. >>> and coming up, our "instan